Apparatus for air conditioning



April 22, 1941. w. w. CUMMINGS, JR

APPARATUS FOR AIR CONDITIONING Filed Sept. 20, 1938 v 3 Sheets-Sheet l In/uen/ior; 1b 731, G

April 1941- w. w. CUMMINGS, JR 2,239,594

APPARATUS FOR AIR CONDITIONING Filed Sept. 20, 1938 3 Sheets-Sheet 2 April 22, 1941. w. w. CUMMINGS, JR 2,239,594

APPARATUS FOR AIR CONDITIONING Filed Sept. 20, 1958 3 Sheets-Sheet 6 40 M Q. y *W GJAM m atented Apr. 22, 1941 2,239,594 APPARATUS FOR Am CONDITIONING William Warren Cummings, Jr., Marshfield,

Mass.

Application September 20, 1938, Serial No. 230,830

18 Claims.

' This invention relates to air conditioning apparatus.

A principal object of my invention is to provide means for positively removing the condensate from the air stream and preventing it from being returned to the air stream thereafter.

In most present methods and apparatus with which I am familiar, it is customary to pass the air through a heat exchanger where the condensate is caused to appear, and which is then carried along in the air stream until removed by impact with baffles located in the air stream. The efficiency of such systems is greatly impaired in that much of the condensate remains in the air stream or is returned to the air stream through evaporation. By means of my invention the condensate is positively removed from the air stream and remains out of the air stream thereafter.

Another'principal object or advantage of my invention lies in providing air conditioning apparatus for controlling the moisture content and temperature of air automatically by using a single air stream and without the necessity of using a second air stream for by-passing the heat exchanger.

Air conditioning apparatus as heretofore usually installed has also required the consumption of very large quantities of water which, as is well recognized, not only involves heavy expense and excessive drain on the city or other water supply, but also, as the use of such apparatus becomes more and more general, tends to overload and damage the sewerage system. Anotherobject of the present invention is to provide an efiicient air conditioning method and apparatus during the practice and operation of which practically no, or only a negligible amount of, cooling water is consumed.

Also, i apparatus of this character, it has heretofore been found necessary to employ relai tively low temperatures in the refrigerating or air cooling mechanism, which are near or below the freezing point, in order to cool the air sufliciently to precipitate the desired amount of moisture, although the desired ultimate temperature of the air may be very much higher, and the temperature differential between the incoming and outflowing air only a matter of a relatively few degrees. It is a-further object of the invention to provide a method and apparatus wherein extremely low cooling temperatures are not re quired, it being possible to employ a cooling temperature little, if any, lower than that of the outside or incoming air in order to effect adequate drying and cooling of the air, even to the freezing point, as in cold storage plants. Where extreme dryness or very low ultimate temperatures are required, and it is desirable to employ somewhat lower cooling temperatures, these will be much higher, however, than the very low temperatures heretofore considered necessary and higher than the ultimate temperature of the cooled and dried air.

In accordance with the general principles of the invention, the incoming air to be dried and cooled is compressed and, as it is compressed, heat is extracted therefrom preferably in such amount that the temperature of the compressed air is substantially the same as its initial temperature, as may also be that at which the cooling medium is maintained, although both may be lower or, under some circumstances, higher. The compressed air is then expanded to substantially atmospheric pressure, whereupon the cooling water employed to carry away the heat extracted from the air during its compression is utilized, under suitable control, to reheat the air to the temperature desired. In order to dispose of the excess heat, the cooling water may be recirculated in a closed system including a spray tower or the like wherein, by reason of the permissible relatively high temperature of the cooling medium, the temperature available for cooling need be no lower than the wet bulb temperature of the outside air.

The compression of the air at constant temperature reduces its volume to such an extent as to raise its relative humidity above the saturation point, so that the excess moisture is precipitated, and, in accordance with one feature of the invention, the compressing means is of such a character as automatically to eject the precipitated moisture from the air stream and cause its immediate discharge from thesystem. When the air is subsequently expanded to its original volume, the moisture, greatly reducedin amount, is redistributed throughout such volume, resulting, particularly if said air is reheated, in a greatly reduced relative humidity. This operation may be better understood by assuming a specific example: e. g., that a given volume of air at a given temperature will, at the saturation point, contain 10 units of water in the form of vapor. If three'such unit volumes of air, at such given temperature, but each containing 8 units of water (i. e., having a relative humidity of becompressed at constant temperature to one unit volume, the latter will contain 24 units of water, but, since it can retain in vapor phase only units, the remaining 14 units will be precipitated out in liquid form. Upon expansion of the air to its original three volumes, the remaining 10 units of water will 'be distributed in the proportion of 3 /3 units of water to each unit volume of air: in other words, the relative humidity will have been reduced from 80% to 25% assuming the restoration of the air to'its original temperature, or slightly higher depending upon the degree of reheating. If'heat be extracted in greater amounts than required to maintain the compressed air at its initial temperature, the reduction of water content during the compression stage will be proparatus shown in the accompanying drawings, 5

these, however, having been chosen for purposes of exempliflcation merely, as it will be obvious to those skilled in the art that the invention, as defined by the claims hereunto appended, may be otherwise embodied and practiced without departure from the spirit and scope thereof.

In said drawings:

Fig. 1 is a diagrammatic view of an air conditioning installation embodying the invention.

Fig. 2 is an enlarged longitudinal section of the compressing. unit.

Fig. 3 isa. transverse section of the unit shown in Fig. 2.

Fig. 4 is a view similar to Fig. 2 of a modified form of compressor.

Figs. 5 and 6 are views similar to Figs. 2 and 3, respectively, showing a further modification.

Referring to Fig. 1, the apparatus .therein shown includes a duct l5 into the inlet end l6 of which air from the exterior atmosphere is admitted, and through which a flow of air to the region to be conditioned is induced by any suitable means, such as a centrifugal blower H. a suitable point in its length, the duct I5 is formed with an enlargement constituting a substantially co-axial cylindrical chamber I8 formed 0 by a cylindrical drum l9 having secured thereto end heads or rings which, in turn, are secured to the ends of the contiguous portions of the duct proper. Disposed co-axially in said chamber I8 is a shaft 2| journalled in suitable bearings carried by spiders which may be formed integral with the heads 20, as shown at 22 in Fig. 1, or may be separately attached to the drum I9, as shown at 23 in Figs. 2 and 3. Supported by radial arms 24 carried by the shaft 2| are longitudinally disposed fan blades 25, the inner edges of which are spaced from the shaft 2| and the outer edges ofwhich are spaced from the drum I9 which constitutes the peripheral wall of the chamber l8. The shaft 2l is rotated by a motor 26 which, as shown in Figs. 1 and 2, is an electric motor supportedby a bracket 21 carried by the adjacent spider 22, 23, and the current to which is controlled as hereinafter described.

Interposed between the outer edges of the fan blades and the peripheral wall of the chamber l8 are cooling elements 28 which as shown in Figs. 1 to 3 comprise the expansion coils of a conventional refrigerating system including a compressor 29 and condenser 30, said compressor having a motor 29a receiving current from line or feed wires L through a circuit comprising conductors 3| and 32, the latter including the usual pressure controlled switch 33 for preventing the building up of excess pressures in the system and also including a solenoid operated switch 34 controlled as hereinafter described.

The circuit to the motor 25 from the line or feed wires L includes conductors 35 and 36 the latter of which is connected with the conductor 32 beyond the switch 34. The conductor 35 includes, in parallel, variable resistances 31 and 38 controlled respectively by a thermostat T and a humidostat H suitably located in the region to be conditioned, whereby the operation of the motor 26 is variably and jointly controlled by the temperature and humidity of the atmosphere of blower I I.

said region. The conductor 36 includes the coil of a solenoid 39 for closing the switch 34, where- I by," whencurrent passes through the circuit to the motor 26, the circuit to the compressor motor 29a will be closed. Thus as temperature or humidity of .the air in the controlled region varies from the desired ratio, or balanced condition, the speed of rotation of the fan will be varied proportionally to correct the condition, and return temperature and humidity to the desired level.

It will now be seen that when the motor 28 is 'in operation to rotate the fan 24, 25, the latter chamber I8, whence it can conveniently be discharged to a suitable point of disposition through a drain pipe 40 without any tendency to return to the air stream flowing through the duct l5. In fact, such tendency is positively prevented by the centrifugal action of the fan. It will -be observed that, while the action of the fan is to draw air from the axial region of the duct at both ends of said fan, such inflow of air is equal and opposite at the respective ends, so that it in no way tends to interfere substantially with the flow of air through the duct under the influence of the The degree of compression of the air may vary as required for the particular installation, as by changing the fan speed, and in other suitable supply can be admitted under the control of a manually operated valve 43, and from the latter of which water may be discharged and drained when desired under the control of a manually operable valve 44. The conduits 4| and 42 are connected by a portion or coil 45 located'in the duct [5 beyond the compressor in the direction of flow of air through said duct.

. It will be understood that the air leaving the chamber l8 after compression, under the influence of the flow induced by the blower II, will again expand in the duct II to its original volume. It the air has been cooled to too low a temperature additional heat may be supplied by the coil 45. It will be observed that this heat is so supplied by the water circulation or cooling system, being received by the latter from the condenser 36, the heat of which is that extracted by the refrigerating system from the air when the latter is compressed.

The water is circulated through the condenser 39 and heating coil 45 by means of a pump 46 operated by an electric motor 41 the circuit 46 through which leads from one of the line or feed wires L to the conductor 35, and includes a thermostatically operated switch 49 located in the duct l beyond the coil 45, whereby the circulation through the heating coil 45 may be controlled by said switch in accordance with the ultimate air temperature desired. I

In order to maintain a circulation through the condenser 30 when circulation through the coil 45 is suspended, and to dissipate the excess heat, a by-pass about the coil 45, including a cooling element such as a spray tower 56, is provided.

This by-pass includes a conduit 5| leading from the conduit 42 to the outlet valve 44, a conduit 52 leading from the conduit 5| to the spray tower 50, and a return conduit 53 from the spray tower to the conduit 4|. This by-pass is controlled by a normally closed, solenoid-opened valve 54 and flow therethrough is induced by a pump 55 operated by an electric motor 56. The circuit to the motor 56, and to the solenoid 51 for opening the valve 54, comprises a conductor 64 leading from the thermostatic switch 49, a branch conductor 58 through said motor and leading to one of the line or feed wires L, and a branch conductor 59 through said solenoid and leading to the conductor 36. The arrangement is such that when the switch 49 is in the position shown in Fig. l to close the circuit through the motor 41, and thereby induce a circulation through the heating coil 45, the circuit to the motor 56 and solenoid 51 is open, so that the valve 54 is closed and the pump 55 idle. When the switch 49 is operated to open the circuit to the motor 41, and thereby suspend circulation through the coil, it acts immediately to close the circuit to the motor 56 and solenoid 51, so that the cooling water is circulated through the spray tower 50. In moving fromone position to the other the switch opens both circuits only momentarily, so that circulation through the condenser 30, by way of either the coil 45 or the spray tower 50, is substantially continuous.

Inasmuch as the cooling temperature required in the compressor for the purpose of extracting the heat of compression is little, if any, lower than the temperature of the air, the refrigerating: system described may, if desired, be replaced by a simple water circulating system in which the compressor 29 would be replaced by a simple circulating pump and the condenser 30 by a suitable heat exchange device. Under some circumstances, the water in the circulating system 4|, 42, etc. may even be circulated directly through the cooling coils 28.

If desired, and as shown in Fig. 4, the electric 'motor' 26 may be replaced by a fluid pressure motor 58, such as a steam or compressed air turbine, to which steam or other fluid pressure is admitted through a conduit 59 under the control of an electrically operated motor valve 60 of any well known type, the operation of which is effected through the circuit 35, 36, under the control ofthe thermostat T and humidostat H in the same manner as the control of the circuit to the electric motor 26 above described, and as will be obvious without further explanation.

In Fig. 4 is also shown a multi-stage compressor, the use of which may be desirable under some conditions. In this arrangement, the shaft 2|, fan 24, 25, and cooling elements 26 are substantially as in the arrangement first described (except that the fluid to the cooling coils 26 is supplied through axial passages 66 in the shaft 2|) but the shaft 2| is provided, beyond the ends of the cooling coils 26, with additional arms 6| carrying a second series of fan blades 62 between which and the peripheral wall l9 of the chamber I8 is interposed a second series of cooling coils 63.

In Figs. 5 and 6 is shown a compressor unit particularly suitable for installations in which it is desirable to employ a relatively high degree of compression as one hundred pounds per square inch, for instance. Such an installation is particularly useful for air conditioning where large air duets cannot be installed, as in remodelling large oflice buildings. As shown, the duct l5, drum l9 and end heads 20 enclosing the pressure chamber I8 with its drainage conduits 40, shaft 2|, and motor 26 are all substantially as in the forms of the invention above described, although, due to the higher pressures employed, the diameter of the duct l5 may be relatively smaller. Secured to the end heads 29 are rings 65, 66 having spiders 61 providing bearings for the shaft 2|, said rings being formed with annular suitably packed bearings 68 for the ends of a tube 69 connected with the shaft 2| for rotation therewith by arms 10. The ring 66 at the outlet end of the unit isof greater axial length than the ring 65 and is formed with ports H to permit flow of air from the pressure chamber It to the duct IS. The tube 69 carries or is formed with a series of centrifugal fans or impellers 12 each comprising a pair of outwardly extending spaced disks 19 disposed transverse to the axis of the shaft 2| and connected by relatively closely spaced radial blades 14, the space between the disks communicating with both the interior and the exterior of the tube 69. In this construction the cooling coils 15 can conveniently be disposed, at least in part, between adjacent impellers l2 and between the endmost impellers and the end heads 20, thereby providing for an increased cooling surface desirable in view of the relatively high pressures generated by this type of apparatus. The detailed design of such a unit will depend upon the degree of air compression desired. As the conditions to be obtained vary, the design necessary to obtain the desired degree ofcompression will vary.

I claim:

1. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, means in said duct for compressing the air during its passage therethrough, said duct being adapted to permit said air thereafter to expand therein to substantially its original volume, means controlled jointly by the temperature and humidity of the-atmosphere of said region for so controlling said compressing means as to vary the rate of compression, and means for extracting heat from said air during compression.

2. An air conditioning apparatus comprising a duet, means for inducing a flow of air through said duct-to the region to be conditioned, means in said duct for compressing the air during its passage therethrough, said duct being adapted to permit'said air thereafter to expand therein to substantially its original volume, and means for extracting heat from said air during compression, said last named means being adapted to restore to said air, after expansion, at least a portion of the heat so extracted.

3. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, said duct having a portion constituting a chamber, a rotary fan in said chamber for centrifugally forcing the air outwardly toward the peripheral wall of said chamber during its passage therethrough,

' and cooling means interposed between said fan and wall.

4. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, said duct having a portion constituting a chamber, a.

wall of said chamber during its passage therethrough, cooling means interposed between said fan and wall, a motor for rotating said fan, and means controlled jointly by the temperature and humidity of the atmosphere of said region for controlling said motor.

6. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, said duct having a portion constituting a chamber, a rotary fan in said chamber for centrifugally forcing the air outwardly toward the peripheral wall of said chamber during its passage therethrough, and a cooling fluidcirculating system including a portion interposed between said fan and wall.

7. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, said duct having a portion constituting a chamber, a rotary fan in said chamber for centrifugally forcing the air outwardly toward the peripheral wall of said chamber during its passage therethrough. a refrigerantcirculating system including a portion interposed between said fan and wall and a heat exchange element, and a water circulating system including said heat exchange element and a portion located in said duct be-' yond said chamber.

8. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, said duct having a portion constituting a chamber, a rotary fan in said chamber for centrifugally forcing the air outwardly toward the peripheral wall of said chamber during its passage therethrough, a refrigerant circulating system including a portion interposed between said fan and wall anda heat exchange element, a water circulating systern including said heat exchange element and a portion located in said duct beyond said chamber, and means controlled by the temperature of the air in said duct beyond said last named portion for circulating water in said last named system.

9. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, said duct having a portion constituting a chamber, a rotary fan in said chamber for ,centrii'ugally forcing the air outwardlytoward the peripheral wall of said chamber during its passage therethrough, a refrigerant circulating system including a portion interposed between said fan and wall and a heat exchange element, a water circulating system including said heat exchange element and a portion located in said duct beyond saidchamber, and means controlled by the temperature of the air in said duct beyond said last named portion for circulating water in said last named system either through said last named portion or independently thereof.

10. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, means in said duct for compressing the air during its passage therethrough, said duct being adapted to permit said air thereafter to expand therein to substantially its original volume, and means for extracting heat from said air during compression, said means including a fluid circulating system having a portion located in said duct beyond the region of expansion of said air.

11. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, means in said duct for compressing the air during its passage therethrough, said duct being adapted to permit said air thereafter to expand therein to substantially its original volume, and means for extracting heat from said air during compression, said means including a fluid circulating system having a portion located in said duct beyond the region of expansion of said air, and means controlled by the temperature of the air in said duct beyond said portion for circulating fluid in said system.

12. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, means in said duct for compressing the air during its passage therethrough, said duct being adapted to permit said air thereafter to expand therein to substantially its original volume, and means for extracting heat from said air during compression, said means including a fluid circulating system having cooling means-and a portion located in said duct beyond the region of expansion of said air andmeanscontrolled by the temperature of the air in said duct beyond said portion for circulating fluid in said system alternatively through said portion or through said cooling means.

13. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, said duct including an enlargement constituting a substantially coaxial cylindrical chamber, a fan in said chamber having longitudinally disposed radial blades spaced from the axis of said chamber, cooling elements interposed between said blades and the wall of said chamber, a motor for rotating said fan, and means controlled by conditions of the atmosphere 01 said region for controlling said motor. I

assas'oa 14. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region "to be conditioned, -said duct including an enlargement constituting a substantially coaxial cylindrical chamber, a fan in said chamber having longitudinally disposed radial blades spaced from the axis of said chamber, cooling elements interposed between the outer ends of said blades and the wall of said chamber, a motor for rotating said fan, and means for draining from said chamber liquid thrown upon the wall thereof by said fan.

15. An air conditioning apparatus comprising a duct having a portion constituting a chamber,

of the atmosphere of said region for controlling said motor. I

17. An air conditioning apparatus comprising a duct, means for inducing a flow of air through means for maintaining a substantially constantqg flow of air through said chamber, a rotary fan in said chamber for centrifugally forcing-air outwardly toward the peripheral wall of said chamber and thereby compressing the same, means for varying the rate of operation of said fan, and means for extracting heat from said air during compression.

16. An air conditioning apparatus comprising a duct, means for inducing a flow of air through said duct to the region to be conditioned, s'aid duct including an enlargement constituting a.

substantially coaxial cylindrical chamber, a coaxial shaft journalled in said chamber, radial arms carried by said shaft, longitudinally disposed fan blades carried by said arms and spaced from said shaft and from the peripheral wall of said chamber, cooling elements interposed between said blades and wall, a motor for rotating said duct to the region to be conditioned, said duct including an enlargement constituting a substantially coaxial cylindrical chamber, a coaxial shaft journalled in said chamber, two sets of radial arms carried by said shaft, .inner and outer longitudinally disposed fan blades carried by said sets of arms, respectively, and spaced from each other, the inner blades being spaced from said shaft, and the outer blades being.

spaced from the peripheral wall of said chamber, cooling elements interposed between said inner and outer blades and between said outer blades and said wall, a motor for rotating said shaft, and means controlled by conditions of the atmosphere of said region for controlling said motor.

18. An air conditioning apparatus comprising a' duct, means for inducing a flow of air through said duct to the region to be coriditioned, said duct including an enlargement constituting a substantially coaxial cylindrical chamber, a coaxial shaft journalied in said chamber, a coaxial tube likewise journalled in said chamber and connected with said shaft forrotation therewith, said tube being provided with impellers each comprising a pair of outwardly extending spaced disks connected by radial blades, cooling elements disposed between said impellers, a motor for rotating said shaft, and means controlled by conditions of the atmosphere of said region for controlling said motor. said shaft, and means controlled by conditions 5 WILLIAM WARREN CUMIIINGS, JR. 

